mysql数据库创建表格出现问题，望赐教！

Question

Operation failed: There was an error while applying the SQL script to the database.
Executing:
CREATE TABLE `managesystem`.`department_manager` (
  `dm_id` INT NOT NULL,
  `user_id` VARCHAR(20) NOT NULL,
  `dm_name` VARCHAR(20) NOT NULL,
  `dp_id` INT NOT NULL,
  `is_onjob` TINYINT NOT NULL,
  `co_id` INT NOT NULL,
  PRIMARY KEY (`dm_id`),
  CONSTRAINT `user_id`
    FOREIGN KEY ()
    REFERENCES `managesystem`.`user` ()
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_bin;

ERROR 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')
    REFERENCES `managesystem`.`user` ()
    ON DELETE NO ACTION
    ON UPDATE ' at line 10
SQL Statement:
CREATE TABLE `managesystem`.`department_manager` (
  `dm_id` INT NOT NULL,
  `user_id` VARCHAR(20) NOT NULL,
  `dm_name` VARCHAR(20) NOT NULL,
  `dp_id` INT NOT NULL,
  `is_onjob` TINYINT NOT NULL,
  `co_id` INT NOT NULL,
  PRIMARY KEY (`dm_id`),
  CONSTRAINT `user_id`
    FOREIGN KEY ()
    REFERENCES `managesystem`.`user` ()
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_bin

以上为错误报告信息，以下为本人在表格输入属性和数据类型后自动生成的sql语句

CREATE TABLE `managesystem`.`department_manager` (
  `dm_id` INT NOT NULL,
  `user_id` VARCHAR(20) NOT NULL,
  `dm_name` VARCHAR(20) NOT NULL,
  `dp_id` INT NOT NULL,
  `is_onjob` TINYINT NOT NULL,
  `co_id` INT NOT NULL,
  PRIMARY KEY (`dm_id`),
  CONSTRAINT `user_id`
    FOREIGN KEY ()
    REFERENCES `managesystem`.`user` ()
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_bin;

本人是直接往表格里输属性和数据类型，没有手敲sql语句，想问现问题出在哪，该如何解决？不胜感激！

Answer 1

你创建外键有问题，先创建表，在添加外键，这种方式也可以

添加外键 ,alter table B

语法bai：dualter table 表名zhidao add constraint 外键约束zhuan名 foreign key(列名) references 引用外键表(列名)

如：

alter table Stu_PkFk_Sc
add constraint Fk_s
foreign key (sno)
references Stu_PkFk_S(sno)

--cc是外键约束名，不能重复，也shu不能是int类型（如1，2，3）

add constraint cc

--B表里的需要约束的字段（id）

foreign key (id)

--A表后的（id）可省略

references A (id)